The Provence class was designed as an enlarged version of the Gloire-class ironclads with thicker armor, more powerful guns, and better seakeeping qualities.

[2] The Provence class carried enough coal to allow them to steam for 2,410 nautical miles (4,460 km; 2,770 mi) at a speed of 10 knots (19 km/h; 12 mph).

[7] In September–October 1866 Magnanime, her sisters Flandre and Héroïne, and the ironclad Magenta participated in fleet maneuvers and comparative gunnery trials.

By 1 April 1870, the ship was assigned to the Squadron of Evolutions (Escadre d'évolutions) and was the flagship of Vice Admiral (vice-amiral) Martin Fourichon.

When they received word that the Prussian ships had returned to Germany, the squadron sailed to Brest to prepare to blockade the coast of Prussia.

The neutral British denied the French permission to re-coal there and the ships were forced to perform it at sea under dangerous conditions.

Bad weather and a series of storms beginning in late August prevented the squadron from coaling and the ships were forced to return to France in early September.

By 21 October 1876 she was the flagship of Rear Admiral Ernest de Jonquières, commander of the Squadron of Evolutions of the Mediterranean Fleet.